1. Field of the Invention
The present invention relates to a shift device with a synchronizer adapted for a transmission in which pushing force applied to a sleeve can be amplified into a larger pushing force acting on a synchronizer ring while gears of the transmission are shifted, thereby reducing operating force required by a driver or an actuator.
2. Description of the Related Art
A shift device with a synchronizer adapted for a transmission of this kind is disclosed in Japanese Examined Patent Application Publication No. 45-35684. This conventional shift device includes a hub and a sleeve, where the sleeve is formed with a slanted surface so that the slanted surface thereof can change a part of friction torque caused between the sleeve and the hub into thrust acting on the synchronizer ring, thereby increasing synchronizing ability. It may add a thrust plate which has slanted surfaces and is arranged between the sleeve and the hub.
This conventional shift device with the synchronizer, however, encounters the following problems.
The slant surface of the hub needs to be formed on the vicinity of a central portion in an axial direction thereof, which requires a difficult manufacturing process for forming the slant surface on the hub, consequently increasing its manufacturing costs.